In recent years, run flat tires having load support layers inside sidewalls have been developed. For the support layers, a highly hard crosslinked rubber is used. The run flat tire is referred to as a side-reinforcing type tire. In this type of run flat tire, if internal pressure is reduced due to puncture, load is supported by the support layer. The support layer inhibits flexure of the tire in a punctured state. Even if running is performed in the punctured state, the highly hard crosslinked rubber inhibits heat generation in the support layer. This run flat tire enables running over some distance even in the punctured state. An automobile having such run flat tires mounted thereon need not have a spare tire therein on a constant basis. The use of this run flat tire allows change of tires in an inconvenient place to be avoided.
When running with the run flat tire in a punctured state is continued, deformation and restoration of the support layer are repeated. Due to the repetition, separation between a bead apex and a carcass ply or damage thereof may occur. Ply loosing may occur between the bead apex and the carcass ply.
Patent Literature 1 discloses a run flat tire in which turned-up portions of a carcass ply, and a belt overlap each other. The carcass has a so-called “ultra-highly turned-up structure”. The turned-up portions overlap the belt, so that generation of the ply loosing is inhibited. The carcass contributes to improvement of durability of the tire.
Patent Literature 2 discloses a tire in which a reinforcing filler layer is disposed axially outward of a bead apex. The tire includes the reinforcing filler layer, so that generation of the ply loosing is inhibited. The reinforcing filler layer also contributes to improvement of durability of the tire.